main.c

klibc精简化的c程序库

      bail:
	packet_close();

	return 0;
}

static int add_one_dev(struct netdev *dev)
{
	struct state *state;

	state = malloc(sizeof(struct state));
	if (!state)
		return -1;

	state->dev = dev;
	state->expire = time(NULL);
	state->retry_period = 1;

	/*
	 * Select the state that we start from.
	 */
	if (dev->caps & CAP_DHCP && dev->ip_addr == INADDR_ANY) {
		state->restart_state = state->state = DEVST_DHCPDISC;
	} else if (dev->caps & CAP_DHCP) {
		state->restart_state = state->state = DEVST_DHCPREQ;
	} else if (dev->caps & CAP_BOOTP) {
		state->restart_state = state->state = DEVST_BOOTP;
	}

	state->next = slist;
	slist = state;

	return 0;
}

static void parse_addr(uint32_t * addr, const char *ip)
{
	struct in_addr in;
	if (inet_aton(ip, &in) == 0) {
		fprintf(stderr, "%s: can't parse IP address '%s'\n",
			progname, ip);
		longjmp(abort_buf, 1);
	}
	*addr = in.s_addr;
}

static unsigned int parse_proto(const char *ip)
{
	unsigned int caps = 0;

	if (*ip == '\0' || strcmp(ip, "on") == 0 || strcmp(ip, "any") == 0)
		caps = CAP_BOOTP | CAP_DHCP | CAP_RARP;
	else if (strcmp(ip, "both") == 0)
		caps = CAP_BOOTP | CAP_RARP;
	else if (strcmp(ip, "dhcp") == 0)
		caps = CAP_BOOTP | CAP_DHCP;
	else if (strcmp(ip, "bootp") == 0)
		caps = CAP_BOOTP;
	else if (strcmp(ip, "rarp") == 0)
		caps = CAP_RARP;
	else if (strcmp(ip, "none") == 0 || strcmp(ip, "static") == 0
		 || strcmp(ip, "off") == 0)
		goto bail;
	else {
		fprintf(stderr, "%s: invalid protocol '%s'\n", progname, ip);
		longjmp(abort_buf, 1);
	}
      bail:
	return caps;
}

static int add_all_devices(struct netdev *template);

static int parse_device(struct netdev *dev, const char *ip)
{
	char *cp;
	int i, opt;
	int is_ip = 0;

	DEBUG(("IP-Config: parse_device: \"%s\"\n", ip));

	if (strncmp(ip, "ip=", 3) == 0) {
		ip += 3;
		is_ip = 1;
	} else if (strncmp(ip, "nfsaddrs=", 9) == 0) {
		ip += 9;
		is_ip = 1;	/* Not sure about this...? */
	}

	if (!strchr(ip, ':')) {
		/* Only one option, e.g. "ip=dhcp", or it's an interface name */
		if (is_ip) {
			dev->caps = parse_proto(ip);
			bringup_first = 1;
		} else {
			dev->name = ip;
		}
	} else {
		for (i = opt = 0; ip && *ip; ip = cp, opt++) {
			if ((cp = strchr(ip, ':'))) {
				*cp++ = '\0';
			}
			if (opt > 6) {
				fprintf(stderr, "%s: too many options for %s\n",
					progname, dev->name);
				longjmp(abort_buf, 1);
			}

			if (*ip == '\0')
				continue;
			DEBUG(("IP-Config: opt #%d: '%s'\n", opt, ip));
			switch (opt) {
			case 0:
				parse_addr(&dev->ip_addr, ip);
				dev->caps = 0;
				break;
			case 1:
				parse_addr(&dev->ip_server, ip);
				break;
			case 2:
				parse_addr(&dev->ip_gateway, ip);
				break;
			case 3:
				parse_addr(&dev->ip_netmask, ip);
				break;
			case 4:
				strncpy(dev->hostname, ip, SYS_NMLN - 1);
				dev->hostname[SYS_NMLN - 1] = '\0';
				break;
			case 5:
				dev->name = ip;
				break;
			case 6:
				dev->caps = parse_proto(ip);
				break;
			}
		}
	}

	if (dev->name == NULL ||
	    dev->name[0] == '\0' || strcmp(dev->name, "all") == 0) {
		add_all_devices(dev);
		return 0;
	}
	return 1;
}

static void bringup_device(struct netdev *dev)
{
	if (netdev_up(dev) == 0) {
		if (dev->caps) {
			add_one_dev(dev);
		} else {
			complete_device(dev);
		}
	}
}

static void bringup_one_dev(struct netdev *template, struct netdev *dev)
{
	if (template->ip_addr != INADDR_NONE)
		dev->ip_addr = template->ip_addr;
	if (template->ip_server != INADDR_NONE)
		dev->ip_server = template->ip_server;
	if (template->ip_gateway != INADDR_NONE)
		dev->ip_gateway = template->ip_gateway;
	if (template->ip_netmask != INADDR_NONE)
		dev->ip_netmask = template->ip_netmask;
	if (template->ip_nameserver[0] != INADDR_NONE)
		dev->ip_nameserver[0] = template->ip_nameserver[0];
	if (template->ip_nameserver[1] != INADDR_NONE)
		dev->ip_nameserver[1] = template->ip_nameserver[1];
	if (template->hostname[0] != '\0')
		strcpy(dev->hostname, template->hostname);
	dev->caps &= template->caps;

	bringup_device(dev);
}

static struct netdev *add_device(const char *info)
{
	struct netdev *dev;
	int i;

	dev = malloc(sizeof(struct netdev));
	if (dev == NULL) {
		fprintf(stderr, "%s: out of memory\n", progname);
		longjmp(abort_buf, 1);
	}

	memset(dev, 0, sizeof(struct netdev));
	dev->caps = default_caps;

	if (parse_device(dev, info) == 0)
		goto bail;

	if (netdev_init_if(dev) == -1)
		goto bail;

	if (bootp_init_if(dev) == -1)
		goto bail;

	printf("IP-Config: %s hardware address", dev->name);
	for (i = 0; i < dev->hwlen; i++)
		printf("%c%02x", i == 0 ? ' ' : ':', dev->hwaddr[i]);
	printf(" mtu %d%s%s\n", dev->mtu,
	       dev->caps & CAP_DHCP ? " DHCP" :
	       dev->caps & CAP_BOOTP ? " BOOTP" : "",
	       dev->caps & CAP_RARP ? " RARP" : "");
	return dev;
      bail:
	free(dev);
	return NULL;
}

static int add_all_devices(struct netdev *template)
{
	DIR *d;
	struct dirent *de;
	struct netdev *dev;
	char t[PATH_MAX], p[255];
	int i, fd;
	unsigned long flags;

	d = opendir(sysfs_class_net);
	if (!d)
		return 0;

	while ((de = readdir(d)) != NULL) {
		/* This excludes devices beginning with dots or "dummy", as well as . or .. */
		if (de->d_name[0] == '.' || !strcmp(de->d_name, ".."))
			continue;
		i = snprintf(t, PATH_MAX - 1, "%s/%s/flags", sysfs_class_net,
			     de->d_name);
		if (i < 0 || i >= PATH_MAX - 1)
			continue;
		t[i] = '\0';
		fd = open(t, O_RDONLY);
		if (fd < 0) {
			perror(t);
			continue;
		}
		i = read(fd, &p, sizeof(p) - 1);
		close(fd);
		if (i < 0) {
			perror(t);
			continue;
		}
		p[i] = '\0';
		flags = strtoul(p, NULL, 0);
		/* Heuristic for if this is a reasonable boot interface.
		   This is the same
		   logic the in-kernel ipconfig uses... */
		if (!(flags & IFF_LOOPBACK) &&
		    (flags & (IFF_BROADCAST | IFF_POINTOPOINT))) {
			DEBUG(("Trying to bring up %s\n", de->d_name));

			if (!(dev = add_device(de->d_name)))
				continue;
			bringup_one_dev(template, dev);
		}
	}
	closedir(d);
	return 1;
}

static int check_autoconfig(void)
{
	int ndev = 0, nauto = 0;
	struct state *s;

	for (s = slist; s; s = s->next) {
		ndev++;
		if (s->dev->caps)
			nauto++;
	}

	if (ndev == 0) {
		if (configured == 0) {
			fprintf(stderr, "%s: no devices to configure\n",
				progname);
			longjmp(abort_buf, 1);
		}
	}

	return nauto;
}

static void set_vendor_identifier(const char *id)
{
	int len = strlen(id);
	if (len >= 255) {
		fprintf(stderr,
			"%s: invalid vendor class identifier: "
			"%s\n", progname, id);
		longjmp(abort_buf, 1);
	}
	memcpy(vendor_class_identifier+2, id, len);
	vendor_class_identifier[0] = 60;
	vendor_class_identifier[1] = len;
	vendor_class_identifier_len = len+2;
}

int main(int argc, char *argv[])
    __attribute__ ((weak, alias("ipconfig_main")));

int ipconfig_main(int argc, char *argv[])
{
	struct netdev *dev;
	int c, port;
	int err;

	/* If progname is set we're invoked from another program */
	if (!progname) {
		struct timeval now;
		progname = argv[0];
		gettimeofday(&now, NULL);
		srand48(now.tv_usec ^ (now.tv_sec << 24));
	}

	if ((err = setjmp(abort_buf)))
		return err;

	/* Default vendor identifier */
	set_vendor_identifier("Linux ipconfig");

	do {
		c = getopt(argc, argv, "c:d:i:onp:t:");
		if (c == EOF)
			break;

		switch (c) {
		case 'c':
			default_caps = parse_proto(optarg);
			break;
		case 'p':
			port = atoi(optarg);
			if (port <= 0 || port > USHRT_MAX) {
				fprintf(stderr,
					"%s: invalid port number %d\n",
					progname, port);
				longjmp(abort_buf, 1);
			}
			cfg_local_port = port;
			cfg_remote_port = cfg_local_port - 1;
			break;
		case 't':
			loop_timeout = atoi(optarg);
			if (loop_timeout < 0) {
				fprintf(stderr,
					"%s: invalid timeout %d\n",
					progname, loop_timeout);
				longjmp(abort_buf, 1);
			}
			break;
		case 'i':
			set_vendor_identifier(optarg);
			break;
		case 'o':
			bringup_first = 1;
			break;
		case 'n':
			do_not_config = 1;
			break;
		case 'd':
			dev = add_device(optarg);
			if (dev)
				bringup_device(dev);
			break;
		case '?':
			fprintf(stderr, "%s: invalid option -%c\n",
				progname, optopt);
			longjmp(abort_buf, 1);
		}
	} while (1);

	for (c = optind; c < argc; c++) {
		dev = add_device(argv[c]);
		if (dev)
			bringup_device(dev);
	}

	if (check_autoconfig()) {
		if (cfg_local_port != LOCAL_PORT) {
			printf("IP-Config: binding source port to %d, "
			       "dest to %d\n", cfg_local_port, cfg_remote_port);
		}
		loop();
	}

	return 0;
}